10,000 per day is roughly how many recitations an average person will complete if they recite at a relaxed pace all day long. If you are awake for 16 hours, this is a mere 625 recitations per hour, about one every six seconds.

Throughout the day, I recite the Nembutsu either out loud or silently. It might give me anxiety, though, if I had a goal for a specific amount of recitations per day. That's just my personal feeling toward the matter.

The purpose of setting a recitation goal is to encourage more nembutsu, which is simply another way of saying we want to think of Amida more often. There's no need to feel anxious about failure or success.

namuamidabunamuamidabunamuamidabunamuamidabunamuamidabu

The Buddhas and Bodhisattvas have unobstructed vision in all directions.
Everything is in their presence; and I stand in front of them. -- Shantideva